1. Field of the Invention
The present invention relates to a data processing device for a sewing machine for preparing stitch pattern data. In particular, the present invention relates to a data processing device for a sewing machine having a needle, material holding means, and a driving device for positioning the material holding means relative to the needle, and for forming a stitch pattern on the material by relative movement between the needle and the material holding means in accordance with stitch pattern data constructed as a data group of 2-dimensional coordinates.
2. Prior Art
Prior to the present invention, such kind of data processing devices are installed apart from the aforementioned sewing machine or integrated therewith. The data processing devices disclosed in U.S. Pat. Nos. 4,413,574, 4,352,334, 4,622,907 and 4,237,803 are well-known. All of them have a basic pattern data memory which previously stores a plurality of basic stitch pattern data for forming a basic stitch pattern, letter symbols, etc. such as ones shown in FIG. 4A. It is generally well-known that desired basic pattern data selected from the basic pattern data memory must be modified through the processes such as inversion as shown in FIGS. 4C and 4D, rotation as shown in FIG. 4B and inclination as shown in FIG. 4E in order to form a desired stitch pattern. Accordingly, the conventional data processing devices include designation switches for each of the above processes. An operator operates the designation switches to prepare the stitch data for forming the desired stitch pattern. However, these conventional devices have some disadvantages. For example, in order to transform a basic stitch pattern shown in FIG. 4A into a desired stitch pattern shown in FIG. 4F, the inclination process shown in FIG. 4E is required after the inversion process shown in FIG. 4C. Therefore, it takes much time to process the data due to complicated operations of the designation switches.